1. Field of the Invention
The present invention relates to an air pressure sensor for impact recognition.
2. Description of Related Art
An air pressure sensor by the applicant which is marketed under the name PPS1 is known. This air pressure sensor measures the pressure in a side portion of a vehicle in the so-called wet space of the doors. The door also has a dry space. The air pressure sensor is installed on the partition between the wet space and the dry space. This is carried out in such a way that either the sensor element is situated in the dry space and the pressure inlet channel projects into the wet space, or the entire air pressure sensor is installed in the wet space. In most cases, the boreholes in the partition which are required for installation must be sealed off using a seal, situated on the sensor, by installing the sensor. However, other fastening principles are also known for which this is not necessary, such as a clip approach, for example. In addition, a seal around the pressure inlet channel is necessary in most applications in which the pressure sensor is installed in the dry space and the pressure inlet projects through the partition into the wet space. For existing air pressure sensors, this seal is achieved using a glued-on sealing foam or an injection-molded seal made of silicone, for example.
The air pressure sensor is designed to be seal-tight against water and media, regardless of the installation site. There are various reasons for this, and with regard to the manufacture, the material requirements, and the requirements for the processor and testing this represents a significant level of complexity in the manufacture of these air pressure sensors. According to the related art, the air pressure sensor has a complicated sealing design, since the air pressure in the sensor is supplied to the pressure-sensitive sensor element, while at the same time all regions in the air pressure sensor which are susceptible to media effects and corrosion must be protected. The inner seal is formed, for example, by a silicone pad which is integrated into the package, the sensor module being pressed against the pad to achieve a tight connection. To protect sensor chips and bonding wires, gelation is usually performed on the pressure sensor diaphragm. The referenced measures represent a significant level of complexity, and may also influence the characteristics of the sensor. Gelation of the diaphragm, for example, requires compound coating of the diaphragm, causing sensitivity to acceleration and thus representing an interfering factor for the air pressure sensor.